Which of the following is a serious threat to underground water supplies?

a) slow recharge rate b) impermeable rock layers
c) infiltration by acidic water
d) contamination by the water table

What do lava flows made of aa indicate about the type of volcanic eruption that occurred? a. the eruption was viscous. b. the eruption was pyroclastic. c. the eruption was explosive. d. the eruption was quite. !

One function of the poly-a tail on eukaryotic mrna sequences is to the mrna be transported from the nucleus to the cytoplasm. prokaryotic mrna also has a poly-a tail. choose the best explanation of the prokaryotic poly-a tail. a. prokaryotic poly-a tails are composed of a different molecular structure compared with eukaryotic poly-a tails. b. prokaryotic poly-a tails have the same functions as eukaryotic poly-a tails, because this process is highly conserved throughout different species. c. prokaryotic poly-a tails aren't important, because prokaryotes don't have nuclei. d. prokaryotic poly-a tails have other functions,because prokaryotes don't have nuclei.

Where does the information about where each transcription factor binds originate?